List of Abbreviations Used Herein:
BS base station
CTRW continuous-time random walk
i.i.d. independently identically distributed
LA location-update area
LAL LA list
LCO LA center optimization
MT mobile terminal
SDF shortest distance first
List of References:
The following references are cited in the specification. Disclosures of these references are incorporated herein by reference in their entirety.    [1] I. F. Akyildiz, J. S. M. Ho, and Y. -B. Lin, “Movement-based location update and selective paging for PCS networks,” IEEE/ACM Transactions on Networking, vol. 4, no.4, pp. 629-638, August 1996.    [2] X. Wang, X. Lei, P. Fan, R. Q. Hu, and S. Horng, “Cost Analysis of Movement-Based Location Management in PCS Networks: An Embedded Markov Chain Approach,” IEEE Transactions Vehicular Technology, vol. 63, no.4, pp. 1886-1902, May 2014.    [3] C. Rose and R. Yates, “Minimizing the average cost of paging and registration: a timer-based method,” Wireless Networks, vol. 2, no. 2, pp. 109-116, June 1996.    [4] K. Li, “Analysis of cost and quality of service of time-based dynamic mobility management in wireless networks,” Wireless Networks, vol. 20, no. 2, pp. 261-288, February 2014.    [5] A. Bar-Noy, I. Kessler and M. Sidi, “Mobile users: to update or not to update?” Wireless Networks, vol. 1, no. 2, pp. 175-185, 1995.    [6] K. Li, “Analysis of Distance-Based Location Management in Wireless Communication Networks,” IEEE Transactions on Parallel and Distributed Systems, vol. 24, no. 2, pp. 225-238, February 2013.    [7] B. Liang and Z. J. Haas, “Predictive distance-based mobility management for multidimensional PCS networks,” IEEE/ACM Transactions on Networking, vol. 11, no. 5, pp.718-732, October 2003.    [8] R. Chen, S. Yuan, and J. Zhu, “A dynamic location management method of personal communication system,” E-Tech 2004, pp. 1-9.    [9] C. K. Ng and H. W. Chan, “Enhanced Distance-Based Location Management of Mobile Communication Systems Using a Cell Coordinates Approach,” IEEE Transactions on Mobile Computing, vol. 4, no. 1, pp. 41-55, January/February 2005.    [10] Y. Zhu, and V. C. M. Leung, “Derivation of moving distance distribution to enhance sequential paging in distance-based mobility management for PCS networks,” IEEE Transactions on Wireless Communications, vol. 5, no. 11, pp. 3029-3033, November 2006.    [11] J. Zhou, H. Leong, Q. Lu, and K. Lee, “Optimizing Update Threshold for Distance-based Location Tracking Strategies in Moving Object Environments,” WOWMOM 2007, pp. 1-8.    [12] Y. Zhu and V. C. M. Leung, “Optimization of Distance-Based Location Management for PCS Networks,” IEEE Transactions on Wireless Communications, vol. 7, no. 9, pp. 3507-3516, September 2008.    [13] Q. L. Zhao, S. C. Liew and Y. Yu, “Location Update Cost of Distance-Based Scheme for PCS Networks with CTRW model,” IEEE Communications Letters, vol. 13, no. 2, pp. 408-410, June 2009.    [14] R. M. Rodríguez-Dagnino, H. Takagi, “Application of renewal theory to call handover counting and dynamic location management in cellular mobile networks,” European Journal of Operational Research, vol. 204, no. 1, pp. 1-13, 2010.    [15] U. Patel and B. N Gohil, “Cell Identity Assignment Techniques in Cellular Network: A Review,” 3rd IEEE International Conference on Computer Science and Information Technology (ICCSIT) 2011, pp. 594-596.    [16] B. Jarupan and E. Ekici, “Mobility management for efficient data delivery in infrastructure-to-vehicle networks,” Computer Communications, vol. 35, no. 18, pp. 2274-2280, 2012.    [17] R. H. Liou, Y. B. Lin, and S. C. Tsai, “An Investigation on LTE Mobility Management,” IEEE Transactions on Mobile Computing, vol. 12, no. 1, pp. 166-176, January 2013.    [18] R. H. Liou and Y. B. Lin, “Mobility Management with the Central-based Location Area Policy,” Computer Networks, vo. 57, no. 4, pp. 847-857, March 2013.    [19] 3GPP, “General Packet Radio Service (GPRS) Enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Access,” Technical Specification 3G TS 23.401, version 10.0.0 (2010-06), 2010.    [20] 3GPP, “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN),” Technical Specification 3G TS 36.300, version 10.1.0 (2010-09), 2010.    [21] H. Fu, P. Lin, H. Yue, G. Huang, and C. Lee, “Group Mobility Management for Large-Scale Machine-to-Machine Mobile Networking,” IEEE Transactions on Vehicular Technology, vol. 63, no. 3, pp. 1296-1305, 2014.    [22] S. Yang, Y. C. Lin, and Y. B. Lin, “Performance of Mobile Telecommunications Network with Overlapping Location Area Configuration,” IEEE Transactions on Vehicular Technology, vol. 57, no. 2, pp. 1285-1292, March 2008.    [23] I. F. Akyildiz, Y. B. Lin, W. R. Lai, and R. J. Chen, “A new random walk model for PCS networks,” IEEE Journal on Selected Areas in Communications, vol.18, no.7, pp.1254-1260, July 2000.    [24] T. X. Brown and S. Mohan, “Mobility Management for Personal Communication Systems,” IEEE Transactions on Vehicular Technology, vol. 46, no. 2, pp. 269-278, May 1997.    [25] Z. Y. Lei and C. Rose, “Wireless subscriber mobility management using adaptive individual location areas for PCS systems” in Proc. IEEE International Conference on Communications, Atlanta, Georgia, 1998, pp.1390-1394.    [26] L. Aleman, E. Munoz-Rodriquez, D. Molina, “FBM mobility modeling for nomadic subscribers,” Proceedings of the 3rd IEEE Symposium Comp. Communications, ISCC, Athens, Greece, June/July 1998.    [27] G. H. Weiss, Aspects and applications of the random walk, Amsterdam, Netherlands: North-Holland, 1994, pp. 95-99.    [28] E. Zauderer, Partial differential equations of applied mathematics (2nd edition), New York: Wiley, 1989.    [29] A. D. Polyanin, Handbook of linear partial differential equations for engineers and scientists, Chapman & Hall/CRC Press, Boca Raton, 2002.    [30] C. W. Gardiner, Handbook of stochastic methods: for physics, chemistry and the natural sciences, Berlin, New York: Springer, 2004.    [31] M. Hellebrandt, R. Mathar, and M. Scheibenbogen, “Estimating position and velocity of mobiles in a cellular radio network,” IEEE Transactions on Vehicular Technology, vol. 46, no. 1, pp. 65-71, February 1997.    [32] B. C. Liu, K. H. Lin, J. C. Wu, “Analysis of hyperbolic and circular positioning algorithms using stationary signal-strength-difference measurements in wireless communications,” IEEE Transactions on Vehicular Technology, vol. 55, no. 2, pp. 499-509, March 2006.
Description of Technical Problem to be Solved:
In mobile communication networks (such as 2G/3G/4G, mobile social networks and mobile cloud computing), the network is partitioned into a number of cells. For location management purposes, an LA consisting of a group of cells is defined as the tracking area of a MT. Location management consists of two complementary components: (i) location update wherein each MT periodically reports its location to the network, and (ii) terminal paging wherein the network pages the cells in an LA to identify the location of a MT upon a request. Location management consumes significant network resources, including wireless network bandwidth and computing time at network nodes.
A variety of schemes have been proposed to minimize the location management cost. Among them, three types of schemes are frequently referenced: movement-based scheme [1], [2], time-based scheme [3], [4], and distance-based scheme [5], [6]. The three schemes differ when a MT performs a location update, i.e. item (i) in the preceding paragraph. Specifically, for movement-based, time-based, and distance-based schemes, a MT performs a location update whenever the number of cells that have been crossed, the elapsed time, and the distance travelled, respectively, exceed a predefined threshold.
It has been shown in [5] that the distance-based scheme consumes the least signaling cost compared with the other two schemes. The distance-based scheme has attracted a great deal of attention [6]-[18] after that. Importantly, the location management scheme in 4G Long-Term Evolution (LTE) [19], [20] shares many essential characteristics with the distance-based scheme, as will be explained in Section G.1. Furthermore, [17] has pointed out the following: through a predefined LA configuration, the 4G LTE can partially implement the distance-based scheme with the shortest-distance-first (SDF) paging [1] for commercial operation; and [17] has evaluated the performance of the 4G LTE location management scheme using the distance-based model [22].
To date, despite substantial existing research results [6]-[18] on the optimization of the LA size, how to set the LA center has not been investigated to the inventor's knowledge. There is a need in the art for determining the LA center and to utilize the result for location updating in mobile communication networks.
Description of Related Art Regarding Location Management Schemes:
In mobile communication networks, most existing research of relevance concentrates on three basic dynamic location management schemes, namely, movement-based, time-based, and distance-based schemes. The authors of [7] proposed a predictive scheme. The authors of [6], [8] and [12] analyzed the location management cost respectively when the cell residence time has a Gamma distribution, when the inter-call time has an exponential distribution and the cell residence time has an arbitrary distribution, and when the inter-call time and the cell residence time have arbitrary distributions. The authors of [10] derived the location distribution of a MT to reduce the paging cost. The authors of [11] optimized the distance threshold in moving object environments. The authors of [14] applied the renewal theory to minimize the location management cost. The authors of [9] and [15] investigated the implementation of the distance-based scheme [5] in which they respectively labeled each cell with the two-dimensional physical coordinate of the cell center or four-digits representing cell positions. The authors of [16] studied efficient data delivery between mobile vehicles and base stations using the distance-based scheme. The authors of [17] evaluated the performance of 4G LTE location management scheme using the distance-based model [22]. The authors of [18] made a simulation comparison between 4G LTE location management scheme and the usual distance-based scheme. Among these studies, only [17] and [18] theoretically analyzed the impact of the movement direction on the signaling cost under the one-dimensional discrete random-walk movement model, but they did not discuss the optimal LA design. Modeling the impact of the movement directionality is equivalent to characterizing the influence of LA center. In the inventor's previous work [13], the issue of minimizing the location-update cost of the distance-based scheme that optimizes the LA center was considered, under a one-dimensional CTRW movement model where a MT moves along a straight line with two movement directions toward left or right, and the length and the time of each movement are continuous.
Different from the previous works, the present work as disclosed herein in the present invention is targeted on the optimal LA design, with an emphasis on movement directionality. Furthermore, the present work as disclosed herein in the present invention substantially and significantly extends [13] to the more realistic and complicated two-dimensional case, investigates both the location-update cost and terminal-paging cost, and studies the joint optimization of LA center and LA size (i.e. the distance threshold).
Description of Related Art Regarding Movement Models:
There has been some previous works on studying the initial position. The authors of [26] investigated fractional Brownian motion with an initial position. However, the focus was on handoff management (addressing how to maintain an ongoing communication) rather than location management (addressing how to track an MT). The authors of [25] considered an adaptive LA with the initial position taken into account. However, the treatment was on one-dimensional Standard Brown Motion, and the update cost incurred by call arrivals was ignored.
Relative to the above works, a distinguishing feature of the present work as disclosed herein in the present invention is that we make a connection between measurable mobility-related physical parameters and the design of LAs.